[The frequency of heteroploidy in spermatozoa of patients with infertility].

The incidence of heteroploid spermatozoa was studied by mono- and dual-colored fluorescence in situ hybridization in semen samples from donors and patients with normal and impaired spermatogenesis. The frequency of heteroploid sperm in the ejaculate was linearly and inversely correlated with sperm parameters (sperm concentration in the ejaculate and proportion of motile and morphologically normal spermatozoa). The level of heterploidy was the most significant in the semen samples from patients with oligoasthenoteratospermia and oligoasthenospermia.

[The specific blocks of heterochromatin on metaphase chromosomes of horse and Prjewalski horse detected by in situ digestion with restriction endonucleases].

Restriction endonuclease in situ digestion of metaphase chromosomes gives an opportunity to reveal strips with different structure within GC-rich pericentric heterochromatin of the domestic horse and the wild Przewalski horse. Blocks of heterochromatin, which are insensitive to HaeIII and brightly stained with chromomycin A3 after restriction enzyme digestion, are localized on the border with euchromatin in the majority of chromosomes of Equus caballus and E. przewalskii.

[Quantitative characteristics of the differential banding pattern prometaphase chromosomes of the domestic horse (Equus caballus)].

A high-resolution cytogenetic map (670 bands per haploid set) of RBA-banded chromosomes has been constructed in the domestic horse Equus caballus. The size and distribution of the replication-based R(G)-bands were analyzed using the computer program VideoTest-Karyo. The obtained data were compared to the results of cytogenetic mapping in other mammalian species and human.

[Distribution of T-bands and telomeric (TTAGGG)n nucleotide repeats on chromosomes of Bos taurus].

Distribution of T-bands on mitotic chromosomes of Bos taurus was studied. Association of T-bands with telomeres and enrichment of T-bands with genes, with a known localization is described. After THA-banding on the chromosomes of cattle, telomeric and pericentromeric regions of all autosomes showed bright fluorescence.

[Analysis of the distribution of ribosomal RNA genes on chromosomes of the domestic horse (Equus caballus) using fluorescent in situ hybridization].

Distribution of blocks of ribosomal RNA genes along metaphase chromosomes of 26 horses from five breeds was determined by means of a modified method of fluorescence in situ hybridization (FISH) in combination with simultaneous R- banding. Gene loci coding for rRNA were mapped to the region of secondary constriction on the short arm of chromosome 1, and to the pericentromeric regions of chromosomes 27, 28, and 31. The nucleolar organizer region (NOR) on chromosome 27 was not described earlier.